Evaporator



Dec. 18, 1956 H. H. BELCHER EVAPORATOR 4 Sheets-Sheet 1 Filed Oct. 25,1951 INVENTOR HAROLD H. BELCHER jaw/5 9% ATI'O EYS Dec. 18, 1956 H. H.BELCHER EVAPORATOR 4 Sheets-Sheet 2 Filed Oct. 25 1951 m a K m w M Y 11i4 Q a fill. k 1 V mi L 6 0 8 6 K lil Z ll 1 i a ll Lw 7 2 9 wk L i wINVENTOR H. BE LCHER HAROLD ATTORNEYS Dec. 18, 1956 H. H. BELCHER2,774,415

EVAPORATOR Filed 001;. 25, 1951 4 Sheets-Sheet 4 I 5 20 l I 76 iii 64 Iv; //0

INVENTOR 59 HAROLD H. BELCHER 2,774,415 7 EVAPGRATOR 'Harold 'H.Belcher, Orange, Mass, assignor't0i'Rodney Hunt Machine Company, Orange,Mass a corpora- "tion of Massachusetts Application October 25, 1951,Serial No.'253,126 15 Claims. (c1. 1596) The present invention relatesto apparatus. for concentrating or evaporating liquids and separatingentrapped liquid from the resulting vapor.

-My invention is illustrated in connection with an evaporator orconcentrator of the type shown in Patent No.

2,596,086 and application Serial No. 216,217, filed March 17, 1951, byHans C. Bechtlerfor Evaporator.

In the concentrating or evaporating of liquids, especially sensitiveliquids such as milk, fruitjuices orthe like, it is important that theliquid be prot'ected from overheating which may injure the flavor,vitamin content, enzyme activity or the like. It has been found thatsuch ov'er heating is most likely to occur at the'bottorn of theevaporator-concentrator where the liquid'i's most concentrated. Therelatively thick viscous concentrate should be kept agitated and shouldbe expelled fromthe apparatus quickly after evaporation.

Another problem in the construction of anevaporiatorconcentrator of thistype is in providing ajsuitableloweir bearing for the rotor since thislower bearing should fulfill a number of exacting conditions. Thebearing -should 'be' such that the rotor maybe easily removed andreplaced for cleaning and'sterilizing. Properflubricationfis importantbecause'the rotor rotates'at fairlyi'high speed and the lower bearing issubjected to fairly high temperatures. Where the bearing is lubricatedby concentrate, lubrication may be inadequate. 'It'is also essentialthat this lower hearing be lubricated 'insu'ch a way that the lubricantdoes not contaminate the liquid being concentrated. I

One of the objects of the present invention isto vide'a thin filmconcentrator-evaporator in which overheating of the concentrate issubstantially'preverited Another object is to provide a thin'filmconcentratorevaporator in which the concentrate is quicklyremovaaafter concentration; I

Another object is to provide a thin 'film concentratore'va'poratorhaving an improved lowerbe'aririg. v

7 Another object isto provide a thin concentratorevaporator in which therotor may be readily inserted and removed.

Another object is to provide a thin filin evaporat'oifconce'ntrator inwhich the lower bearing may be readily removed and replaced.

Another object is to provide a thin film-evaporatorconcentrator whichmay be effectively lubricate-d smiss:

contaminating the liquid being concentrated or evaporated.

These and other objects and advantages reside in certain novel featuresof construction arrangement and cornb'ination of parts as willhereinafter be more rally-set forth and pointed out in the appendedclaims.

Referring to the drawing:

Figure 1 is a vertical section of the upper part of'a thin filmevaporator concentrator embodying my invention;'

Figure 2 .is a vertical section of the lower part'th'ereof;

Figure 3 :is an enlarged verticalsection 'of the lower bearing and vanestructure of a thin film evaporator enibodying my invention;

, Figure 4 is a fragmentary horizontal section taken' 'on line 44 of'Figure'3; V

, Figure 5jis a fragmentary vertical section taken an line;5+-5 ofFigure 3;

Figure 6 is an enlarged fragmentary vertical section 2,774,415 PatentedDec. '18, 1956 ice 2 ofa'modifi'ed form of the lower bearing andoutletsection of the apparatus;

Figure 7 is'a'plan view of the bottom-' plate of the apparatus of Figure6 shown removed from the-assembly;

Figure 8 is an enlarged fragmentary vertical section of a'furthermodification of the discharge section of the apparatus;

Figures is a fragmentary section taken along 'line'9' '9 of FigilfeiS;and

Figures .10 and ll-ar e "fragmentary views of a man- 'fied 'Tdischargepipe installation which may be incorporated in the apparatus 'm'Figure8. p

The general construction of an "eflicient film -'evaporatonconcentratoris described and-claimed in the aforesaid .Patent 2,596Q086 andapplication Serial No.

:is' of tubular construction andis normallyjoper'ate dinverticalzpos'ition. The lower portion, indicated generally at 10, .-is'the evaporator'portion iof theapparatus 'and the upper portion,indicated generallyat 12, is the-separator portion; The liquid --to beconcentrated is introduced :'through aj'pipe or fitting 14 Whi'cll'isgenerally located between thefevaporator 10 and' separ'ator 12 and flowsdown through the evaporatorf10 byrgravity. The con- .centrated liquid iswithdrawn through a pipe or fitting 1:6 at the bottom of the evaporator=10 and vapor is discharged through a' pipe or conduit :18 abovetheseparator 12. V

The evaporator portion has a wall 20 which is normally cylindricalthroughout substantiallytheentirelength 'of-the evaporating chamber.Thiswall 20 may betap'ered toform'a frusto-conical ratherthan-a'cylindrical'chamber and, while a cylindrical chamber isordinarily vpreferred, it is to be understood that the term cylindricalwhen applied to the evaporator includes also a chamber of tapered orconical form.

The separating chamber 12 may be a'continuation of the evaporatingchamber or may be larger-or' smaller than the evaporating chamber 10 butin the :preferred form", the separating chamber 12 formed by a wall 22.is'of larger diameter than the evaporating cha'mberzand the walls 20 and22 are connected bya conical wall '24. A 'flange 26 is secured aroundthe upper end of the "wall 22, above the pipe or conduit 18, and :isreinforced by braces. 28 van'd30 secured to pipe 18 and -a second pipe32 respectively. These braces 28 311(1 may be welded to the ring 26 andto thepipes 18 and 32.

The top of the apparatus is closed by acap 34 re-- movahly secured onthe top of wall 22 and' ring.26by screws or bolts 36 and a suitable:gasket 38 insures a pressure-tight seal. 7

An extension 40 on top of the cap 34 carries a bearing housing 42 at itsupper end for receiving suitable bearings indicated generally at 44. Thespecific construction of these bearings forms no part of thepr'esentinverition but they are preferably of the anti-friction,self-aligning type. A shaft 46 is rotatably mountedv in the bearings 44and the housing 42 is provided with oil seals 48 atits upper and lowerends to prevent leakage of oil along, the shaft. The shaft 46 inayalsobe provided with an oil-flingercup 50 between the bearing housing andthe cap 34 to 'aflord further protection against the leakage of oil orlubricant along the shaft.

A suitable pressure seal such as the water seal indicated generally at52 is usually provided between the shaft 46 and cap 34 and varioussatisfactory 'forms of pressure seal are "known. A conical wall 54extends between "joint of wall 22 and ea 'sa and the lowerend ofthepressure seal 52 and serves to reinforce the pressure seal and protectit from the hot vapors.

The shaft 46 isarelatively short and is' detachably secured at its lowerend to the rotor 56 as indicated generally at 58.

This connection is preferably protected from the hot vapors by a cap 60.This cap also simplifies the cleaning and sterilizing of the rotorassembly. a The rotor 56 of the apparatus is coaxial with the shaft 46and could be a solid shaft but is preferably of tubular construction tosave weight and cost.

The connection 58 between shaft 46 and rotor 56 is accessible throughthe large pipe or handhole 32 which is usually opposite the pipe orconduit 18 and isnormally closed by a door 62. The pipe or handhole 32is sufiicientlylarge to permit a workman to reach into the chamber 12for various operations such as adjustingor examining the seals54,-disconn'ectingthe shaft 46 from the rotor 56'so that the cap, 34.and.shaft.46 may be removed as a, unit for cleaning .or repairing theapparatus or the'like.; Suitable means such as a gasket is provided toform a pressure seal between .the door 62 and handhole 32.

In my preferred form of apparatus, an annular flange V 64 is weldedaround the lower end of the wall 20 and a .flat plate 66 is, detachablysecured to theflange 64 by bolts '68. ,A gasket 70 formsa pressuresealbe twe'en the .flange 64 and'plate 66. l I

.A sleeve 72 is. welded to the plate 66 and extends into the chambersubstantially concentric with the wall 20.1, A bearing 74 which Ipreferto be of the waterlubricated type, is secured within the sleeve72.. -Many suit- 'able bearingrnaterials are known and variousrubbergraphite compositions are entirely satisfactory The sleeve .72 andbearing 74 are reinforced by 'a'frustoconical wall 76 which is welded tothe sleeve 72 and plate The rotor 56 extends through the entire lengthof the separating cha'mber'12 and evaporating chamber 10 and a plug'or'ring 78 is threaded, welded or otherwise rigidly secured in the rotor. Astub shaft 80 in axial alinement with the shaft .46 is threaded, weldedor otherwise firmly secured in the plug or ring 78' and'projectsdownwardl therefrom into the bearing-74. a

As shown in Figures 2 and 4, the rotor 56 extends downward beyond theplug or ring 78 outside the sleeve .72 into. close proximity 'with theconical wall 76; The sleeve 72'.extends upward beyond the bearing 74into close proximity with the plug or ring 78 and protects -pheral notchrespectively of the bearing 74 so that the lubricant, preferably water,may be, introduced through the. opening 86 and withdrawn through the.opening'88 by suitable means, not shown. The openings 86 and 88 aremaintained under vacuum,-substantially the same asthe vacuum' on outlet16 as hereafter described. In i order. to keep the lubricant fromflowing over the sleeve 72'where it might contaminate the concentrate,

the stub shaft 80 is provided with a flinger ring 90' and the upper endof the sleeve 72 is recessed as indicated 'at 92, oppositethe flingerring 90 so that the lubricant is returned to the top of the bearing 74and withdrawn through grooves 82, notch .84 and'opening 88. e

The evaporating chamber 10 is preferably heated by a steam jacket formedby the Wall 94. and steam is introduced through a pipe 96 at the upperend of the jacket and is exhausted through a pipe 98 at the lower end ofthe jacket. 7 provided to exhaust the air from the steam jacketwhenoperation is started and the wall 20 is preferably provided with ;meanssuch as rings 102 at intervals toremove condensation from the surface ofwall 20 allowing maximum contact of the steam. 1 a

If desired, an exhaust pipe may be The rotor 56 is imperforatethroughoutits length and is sealed at'both ends. The rotor 56 is smaller than theevaporating chamber 10 formed by the wall 20, and within the chamber 10,and is provided with a plurality of blades or vanes 104 which extendoutward from the; rotor into close proximity with the wall 20. In the embodiment shown in Figures 1' and 2, there are four equally spaced vanesor blades 104 which project radially outward toward the wall 20.Ordinarily the vanes 01'' blades 104 are fiat strips of metal or thelike and may be rigidly secured along one entire edge to the rotor 56'by. welding or the like, or the inner edges of the vanes.

may be recessed as indicated at 106 and the vanes welded to the rotor atspaced points as indicated at 108. This latter construction is lesscostly than the first form' but the first form may be easier 'to cleanor sterilize. It is not essential that the vanes104 be flat radially northat they extend longitudinally along the rotor but the fiatlongitudinal vanes are simpler to make and attach to. the V rotor andare also lighter in weight.

The vanes 104 are continuous longitudinally and from the rotor 56 toclose proximitywith the wall 20 so that every part of the space betweenthe rotor 56 and wall 20 is acted upon by the vanes 104 when the rotoris rotated. Holes, notches or perforations in the vanes 104 will notprevent satisfactory operation so l'ong as 20 is kept as small aspossible within reasonable mechanical limitations. Any number of vanes104 maybe used but, because of the small clearances, it is importantthat the rotor 56 be balanced and the vanes are therefore preferablysymmetrically disposed about the rotor.

As shown in Figure 2, the rotor 56 and vanes104 extend a substantialdistance below' the bottom of the steamjacket into close proximity tothe plate 66. The liquidat the lower part of the evaporator 10 isusually quite thick and susceptible to, burning, especially if any- 7foam or liquid is allowed to collect in this lower portion.

,The vane portions below the steam jacket keep the foam and liquidagitated and by stopping the steam jacket short of the bottom, the foamand liquid are protected from excessive heat. My improved constructionfurther protects the concentrate from over-heating by forcing theconcentrate out of the apparatus.

The outletopening 16'is located adjacent the wall 20 and thefrusto-conical wall 76 extends downward and .outward from the sleeve72'into close proximity to the inner edge of the outlet'opening '16.This frusto-conical wall thus acts with the centrifugal force on theconcen- 1 hate due to the action of-the rotor 56, to forcetheconcentratedownward; and outward, toward the outlet opening. I 7

Further, the lower ends of the vanes 104 are bent rearwardly of thedirection of rotation asindicated at 110 in Figure 5 and these curvedlower ends serve-'to force, the concentrate downward toward the plate66' and outlet opening 16.

In each of the embodiments illustrated, thevanes 104 continue; along therotor up into the separating chamber ,12 and a grid, consisting of aplurality of vertical,1radia1ly I vertical bafiles 112 and 114 arepreferably welded together so that the entire grid may be inserted orremoved from. the separating chamber as a unit. There is preferably aclearance between the lower horizontal bame ama- 1s 'Z1 14andthewall-'22 so that'liquid can run downfthe wall 22-without interferenceand the top horizontal baflle 114 Eispreferably-higherthan the upper'endsof vanes 104 "as s'hown'in -Fig'ure 1. The baflies 112 and 114extend inward into close proximity to the vanes 104 so that thevap'or'cannot pass through the separating chamber without being actedupon by the vanes.

iAs' p'ointed out above, the evaporator-concentrator is operated '-in avertical position and mounting brackets 116 r'n'ay besecured 'to theapparatus for securing the apparatus to suitable supports.

1' Theiapparatus is usually'operated under a vacuum and :a'condenser andpump,'notsho'wn, which may be of any suitable construction, areconnected to the vapor outlet c'ohduitlS. The concentrate is dischargedthrough the -pipe 16 and asuitable'trap, or pump, notshown, whichmaintains --the vacuum.

#In operationQthe shaft 46 maybe provided with a pulley, not-shown,above the bearing housing 42 and be driven by a suitable source of powersuchas an electric motor, not shown. The rotor is rotated rapidly butthe exact speed of rotation is not critical. The operation 'issuccessful when the shaft 46 and rotor 56 carrying the vanes 104 arerotated at a speed such that the circumferential speed of the vanes 104is in thelg eneral rangeof ten to fifteen meters per second.

.The liquid to be concentrated is introduced through the pipe 14 whichis ordinarily above the steam jacket to avoid burning of the incomingliquid and is preferably between the evaporating chamber 10 andseparating chamber 12 although it may be located in the separatingchamber 12. If desired,'a plurality of inlet pipes 14 .may' besymmetrically disposed around the wall 20 to equalize the cooling effectof the liquid and notches 118 may be provided in the vanes 104 oppositethe inlet 14 to facilitate introduction of the liquid to beconcentrated. .The wall 20 is heated by introducing steam at the desiredtemperature and pressure and the vanes 104 force Tthe liquidout againstthe heated wall'20 in a thin film. The liquid flows down the wall 20 bygravity to the bottom of "the evaporator housing and is withdrawnthrough the pipe 16. As the liquid fiows down the wall 20, vapor isdriven off and this vapor passes upward between the rotor 56, wall 20and the vanes 104 The moving vanes 104 drive entrapped droplets of foamor liquidoutward against the wall 20.

The rotor 56 is usually of fairly large diameter relative to thediameter of the evaporating chamber 10 and the vanes 104 are relativelynarrow since narrow vanes are stronger and more rigid than wide vanes.However, it is desirable that there be sufiicient space between therotor 56 and the wall 20 so as not to impede or unduly restrict thepassage of the vapor upward through the evaporating'chamber 10.

Because the rotor 56 is imperforate and the vanes 104 are substantiallycontinuous longitudinally and radially, the entire contents of theevaporating chamber 10 is at all times subject to centrifugal forceresulting from rotation of the rotor and vanes. This tends to suppressthe formation of foam and to force any foam which may be formed outwardagainst the heated wall 20. Likewise, the rising vapor must pass betweenthe vanes which tend to drive entrapped liquid or foam particles outwardagainst the heated'wall 20. There is no place within the steam jacketportion of the evaporator portion 10 where liquid or foam can collectfree from the action of the rotating vanes 10 All of the vapor from theevaporating chamber 10 passes upward through the separating chamber 12which ,-is'norm'ally unheated except by the vapor. Ordinarily .thetemperature in the separating chamber 12 is insufficient to causesubstantial further evaporation of the liquid. The purpose of thisseparating chamber is to remove any unevaporated foam or liquid carried:by the vapor so that operating losses may be kept as low as 6,6 7 r l fl ille tf tfm yl egin'ec s'sia jy- 1 lblelto supply som outside jhjeatrogthejwallgzz =to pr vent" condensation in gthe. separatingchamber-Which "m yqpc r'l I i to ensure' e' ractionofliq'uids-vvhicharegiiot'feasily,separated from their 'vap'ors. Such'heat fshou'ld, however, he kept at a minimumjto avoid burning theseparated 'liquidfflowing down the wall 22. a Inthepreferred fd m'ofseparator'jshown, the length and Ispeed'of rotation 'of the rotor 56and 'van'esf104 in the separating eonejl'is suchfthatithe vanes willmove thrgugh at llea s'tjthe ,angular' distance between adjacentyanswliile vaporjis moving the length of the 'vanesvin "t e weat n 19, ta e ry pa t-b v pbr ri s' 15 ing through the separating zone "is acted'upon byfa-"v'ane 104 moving through theyapor and. any -en'trapped roamor liquid will bejdrivenoutwardjbyjcentrifugalforce toward the wall 22.The'yertical bafiies -112prevent roa o o tha'ss a 'a m-a d liqu within mnt ratingphamberand thejhorizont'al baffles 114 preventthe separatedfoam and liquid from being carried upward by the vapor. The jtop'horizontal bathe-is located [above the ends of fthe, vanes 104 toprevent the vapor from 'carrying entrappedgfoam or liquid over the topof the grid. Any foamjand'liquidfinthevapor injthefsep'ar'atins hamb i zPl'0i m w against the wa l by the vanes;104 andflowsdown the,,walls.22and 24 b sk nt jthe vaporatin c m e as. pointed out in applicationSerial No. 2l6, 2l7., of Hans C. B e'cht ler referred to above, it isimportant that .the apparatus be easy to take apart for cleaning. and teli i V 1 m zapaal'al .th cpm ct n '5 m y b ched through handhole 32ja'ndShaft?! disconnectedfro'm the 35 rotor 56. The cap 34carrying theshaft'46 may then be removedand the rotor 56- left in place with thepluglor ring 78 resting on the "sleeve 72. The interior of the apparatusmay then be cleaned with a brush or by flushing. If more c ompletecleaning or sterilizih'g 'isfdesired-the 40 cap 34, shaft 46 and rotor56 maybe removed as a unit and cleaned and sterilized outside theapparatus. The separator grid may be removed after removal of the cap 34with or without removing .the rotor 56. i

If it is necessary or desirable to remove; the lower bearing forcleaning or sterilizing o-rforreplacement or repair, the plate 66 andentirebea'ring unit can be removed without disturbing the rest of theapparatusby removing the screws or bolts 68.

The apparatus described above has been foundfto be particularlyeffective in the production of concentrates haying relatively lowviscosity.

However, to facilitate .efiicient removal ofthe more viscousconcentrates 'such as eggs 'and gelatin, particular- 1y whensuchsubstances are concentrated to 50% .solids or greater themodifications of the discharge-.section of the apparatus shown. inFigures, o through ll of the drawings may be preferred.

Referring'now more particularly to Figure 6,it -will.be seen that thebottom plate 66 has been replaced flw'ithra bottom plate 120, to whichthe'bearing; sleeve '72 and cone 76 are secured in the same manner asdescribed in connection withFigure 3. The plate 12 0.is clampedhetweenthe flange 64 and a ringl22 by means of a plurality of bolts, not shown,which extend through the 65 ring 122, plate 120 and flange 64. Coredpassages 124 and 126 are formed'in plate 120 for the purpose ofsupplying and withdrawing lubricant respectively in the-mam nerpreviously described. The outer ends of the passages 124 and 126 may beconnected to a suitable lubricant circuit, not shown. Four arcuate slots128 are provided in the plate 120, directly beneath the rounded tips ofthe rotor vanes, through which the concentrate may be discharged into aconical receiving section 130, which .is preferably welded at its upperend to the ring 122. At its lower end the conical section 130 carries athreaded fitting for attachment to a suitable container or pipe.

and. sterilizing.

Except for the modifications justdescribed, the evaporator-concentratorapparatus of Figure 6, is identical to that illustrated in Figures 1 and2. The concentrate is forcedvthrough the slots 128' by the action of thevanes and the vane tips 110,'as in the case of discharge pipe 16,

the principal difierence being in 'the enlargement of crosssection ofthe discharge passages.

In the modification of Figure 8, the bottom plate 66 has been replacedwith a detachable discharge section comprising a bottomplate 140, weldedto a tubular secinstallation of the tubular section'142; A'seal 150 isprovided at the juncture of tubular sections 20 and 142, to

'efiect a fluid-tight connection atfthis point. Lubricant 'passages 152and 154 in plate '140 function' in the same 'manner' as passages 86 and.88 "previously' described. It

will be noted thatthe conicalreinforcing wall 156 which replaces thewall 76, has been extended almost to the tubular section 142. Thecontour of the bottom of the vanes 104 has been modified accordingly.The rounded construction of the lower tip ofthe vanes'may' be retained.However, the vanes will function properly if the 'vane tips are straightand coplanar with the vane body. The dischargepipe 158 is welded to thetubular section 142, and extends tangentially therefrom as seen inFigure 1 9,"exte'nding' downwardly at an angle preferably in theneighborhood of 45 or less, with respect to the plane o'f the bottomplate 140. By virtue of this construction, full advantage is taken ofthe centrifugal throw of the rotor blades, 'and the concentrate is taken"off the 1211142 7 tangentially of the direction of flow oftlieconcentrate thus insuring a satisfactory discharge evenwhere highlyviscous concentrates which tend to cling to tubular wall 142 areproduced.

The discharge pipe 162, illustrated in.Figures l and 11 which isinstalled at the intersection of the bottom plate and the verticaltubular section is arranged to take full advantage of both thecentrifugal and vertical flow components imposed on the concentrate bythe rotor blades 104 which revolve in the directionindicated by thearrow. This installation of the discharge pipe would be most effectivelyutilized in a'disch'arge' section of. the type illustrated in Figure 8,modified so as to bring the slope of the reinforcing cone into agreementwith that shown in Figure 3.

7 It is believed that the tangential discharge pipe installations shownin Figures 8' through: 11- will have particular utility in handlingcertain highly viscous concen- 'trates which are apt to'cling to thevertical wall of the apparatus, although the lighter and less viscousconcentrates, which fall readily to the bottom plate, rnay be handledefliciently by the apparatus illustrated in Figures l7.

It will be understood that the apparatusof Figures 6 through 11 may bepartially or wholly disassembled for cleaning,'inspection or repairs inthe same manner as the apparatus of Figures 1-5. e

It is also to be noted that, where operating conditions require,additionaldischarge pipes or openings may be incorporated in all formsof the apparatus.

From the foregoing it will be apparent that I am able to'attain theobjects of my invention' and provide a new and improved apparatus forconcentrating liquids in which operational losses are minimized. Theapparatus is simple in construction and the parts are so made that "the.apparatus maybe readily disassembled for cleaning 7 The invention maybeembodied in other specific forms without departing from the spirit oressentiahcharacterstrictive, the scope of the invention being indicatedby 'the lower surface of the flange 148, to permit theflush Z outlets.

the appended claims rather than by the foregoing description, and allchanges which come within'themeaning and range of equivalency of theclaims aretherefore in tended to be embraced therein. p y

What is-claimed and desired to be secured by United States LettersPatent is: a .1. In an evaporator, including a, chamber having asubstantially vertical cylindrical wall, a rotor rotatably mounted insaid chamber substantially coaxial with said wall, a plurality of vanesradially spaced around said rotor and extending outward therefrom intoclose proxim ity with said wall, means for rotating said rotor, meansatthe upper end of said chamber for introducingliquid to be evaporated,and heating means on said wall below said inlet; a substantially flatplatedetachably secured to said chamber and closing the lower endthereof; and'said plate having a plurality of circumferentially spacedoutlets for unevaporated concentrate, a downwardly and outwardly flaredmember secured atits base to said plate within said chambersubstantially centrally of saidchamher, the outer edge ofsaid memberbeing adjacent said outletsi to deflect the concentrate outward: towardsaid 7 outlets and bearing structure for said rotor rigidly secured tosaid plate, said plate having a first passage for.

supplying lubricant to the center of said bearing structure and anadditional passage for removing lubricant from thereof 7 2 An evaporatoras defined in claim; l in which the vanes extend downward into closeproximity with said plate and said conical member.

3. Anevaporator as defined in claim 2 including means on the lower endsof the vanes for urging the unevaporated concentrate downward andoutward toward said said bearing structure at a point adjacent theperiphery 4. An evaporator comprising a wall forming a verticallyelongated chamber, a rotor having a'coaxial open cylindrical-portionforming an open lower end thereof, said rotor being mounted for rotationin-said chamber substantially coaxially with said wall, a plurality ofvanes radially spaced around said rotor, and 'extendingoutwardlytherefrom into close proximity with said wall,

I means for rotating said rotor, means at the upper end of .said chamberfor introducing a fluid to be evaporated,

a substantially flat plate detachablysecured to saidchan her and closingthe bottom thereof, means forming an outlet for unevaporated concentratein the lower end of said chamber, a stub shaft secured within said opencylindrical portion or said rotor and coaxial therewith, a bearingassembly secured to .said plate .Withinsaid chamber coaxial with saidwall for rotatably and slidably receiving said stub shaft comprising anouter cylindrical sleeve, an inner cylindrical sleeve of anti-frictionmaterial,

saidinner sleeve being concentric with and shorter. than.

said outer sleeve and the upper part of each of said sleeves extendinginto said open cylindrical portion of i said rotor, means, forintroducing lubricantwithin said isticsthe'reof. The present embodimentistherefore to r inner sleeve, means for preventing lubricant frompassing over said outer sleeve, means for withdrawing lubricant frombetween said sleeves, a frusto-conical member en circling said bearingand secured at. its upper end tozsaid bearing and at its lower end-tosaid plate, said member being secured to the plate at substantially thesame distance from the center of the plate as the inner edge of saidoutlet, the vanes on said rotor extending into 1 close proximity to saidmember and said plate, and means for.

said inlet to a point spaced above said plate.

heating the wall of said chamberfrom a point beneath 5. An evaporator asdefined in claim 4 including '7 .means for releasably securing saidplate and bearing'to said wall in fluid pressure tight relation thereto.

6. An evaporator as defined in claim 4 in;which the heatingmeanscomprises a heating jacket surrounding said wall from beneath said inletto a point adjacent the top of said bearing.

7. In an evaporator including a chamber having a substantially verticalcylindrical wall, a rotor comprising a hollow tube rotatably mounted insaid chamber substantially coaxial with said wall, a plurality of vanesradially spaced around said rotor and extending outward therefrom intoclose proximity with said wall, means for rotating said rotor and meansat the upper end of said chamber for introducing liquid to beevaporated; a plate closing the bottom of said chamber, means forming anoutlet for unevaporated concentrate in said plate adjacent said wall, astub shaft secured within said tube adjacent the lower end thereof andcoaxial therewith, a hearing secured to said plate within said chambercoaxial with said wall for rotatably and slidably receiving said stubshaft, and a frusto-conical member encircling said bearing and securedat its upper end to said bearing and extending downwardly and outwardlyinto engagement with said plate adjacent the inner edge of the outlet todirect unevaporated concentrate toward said outlet.

8. An evaporator as defined in claim 7 in which the hollow tube of saidrotor extends downwardly over the upper part of said bearing into closeproximity with the top of said frusto-conical member, and the vanes onsaid rotor extend downward from said tube into close prox imity withsaid frusto-conical member and said plate.

9. In an evaporator, including a chamber having a substantially verticalcylindrical wall, a rotor rotatably mounted in said chambersubstantially coaxial with said wall, a plurality of vanes radiallyspaced around said rotor and extending outwardly therefrom into closeproximity with said wall, means for rotating said rotor and means at theupper end of said chamber for introducing a liquid to be evaporated; asubstantially flat plate closing the lower end of said chamber, saidplate having a plurality of circumferentially spaced openings to provideoutlets for unevaporated concentrate, and a downwardly and outwardlyflared member secured at its base to said plate within said chamber, theouter edge of said member being adjacent the inner edge of said'circumferentially spaced openings to deflect concentrate toward saidoutlets.

10. An evaporator as defined in claim 9, together with a conicalreceiving member for the concentrate and means detachably securing saidmember to the lower side of said plate.

11. 'In an evaporator including a chamber having a substantiallyvertical cylindrical wall, a rotor rotatably mounted in said chambersubstantially coaxial with said wall, a plurality of vanes radiallyspaced around said rotor and extending outward therefrom into closeproximity with said wall, means for rotating said rotor, and means atthe upper end of said chamber for introducing a liquid to be evaporated;a discharge section adapted to be detachably secured to the lower end ofsaid evaporator, comprising a tubular member forming a continuation ofsaid vertical cylindrical wall, a substantially flat plate rigidlysecured to the lower end of said tubular member to close said chamber,an outlet for unevaporated concentrate in said tubular member adjacentsaid plate and a downwardly and outwardly tapered member secured at itsbase to said plate within said chamber, the outer edge of said memberbeing adjacent said outlet to deflect the concentrate toward saidoutlet.

cumferentially spaced openings to provide outlets for unevaporatedconcentrate, a bearing structure on said plate for rotatably andslidably supporting said rotor substantially centrally thereof, saidplate having inlet and outlet passages for lubricant for said bearingformed in the portions of said plate intermediate said openings, and adownwardly and outwardly flared member secured at its base to said platewithin said chamber, the outer edge of said member being adjacent theinner edge of said openings to deflect concentrate toward said outlets.

13. An evaporator as defined in claim 12 together with a conicalreceiving member for the concentrate, and means detachably securing saidmember to the lower side of said plate.

14. An evaporator comprising means forming a vertically elongatedchamber of circular section, a rotor rotatably mounted in said chambersubstantially coaxially thereof, said rotor having a stub shaft adjacentits lower end, means for rotating said rotor, means at the upper end ofsaid chamber for introducing a liquid to be evaporated, a platedetachably secured to said chamber and closing the bottom thereof, saidplate having a plurality of circumferentially spaced openings formingoutlets for unevaporated concentrate, a bearing assembly mounted on saidplate within said chamber coaxial with said wall for rotatably andslidably'receiving said stub shaft, said bearing assembly comprising anouter cylindrical sleeve, an inner cylindrical sleeve of anti-frictionmaterial, said inner sleeve being concentric with and shorter than saidouter sleeve, means forming radially extending inlet and outletlubricant passages in said plate, said inlet passage communicating withthe interior of said inner sleeve and said outlet passage communicatingwith the interior of said outer sleeve, a frusto-conical memberencircling said bearing and secured at its upper end to said bearing andat its lower end to said plate at substantially the same distance fromthe center of the plate at the inner edge of the outlet, and means forpreventing lubricant from passing over the said outer sleeve into theinterior of said chamber.

15. An evaporator comprising means forming a vertically elongatedchamber of circular section, a rotor rotatably mounted in said chambersubstantially coaxially thereof, said rotor having a stub shaft adjacentits lower end, means for rotating said rotor, means at the upper end ofsaid chamber for introducing a liquid to be evaporated, a platedetachably secured to said chamber and closing the bottom thereof, saidplate having a plurality of circumferentially spaced openings formingoutlets for unevaporated concentrate, a bearing assembly mounted on saidplate within said chamber coaxial with said wall for rotatably andslidably receiving said stub shaft, said bearing assembly comprising anouter cylindrical sleeve, an inner cylindrical sleeve of antifrictionmaterial, said inner sleeve being'concentric with and shorter than saidouter sleeve, means forming radially extending inlet and outletlubricant passages in said plate, said inlet, passage 12. In anevaporator including a wall forming a ver- I communicating with theinterior of said inner sleeve and said outlet passage'communicatin'gwith the interior of said outer sleeve, a conical receiving member forthe concentrate and means for detachably securing said mem- I her to thelower side of said plate, and means for preventing lubricant frompassing over said outer sleeve into the interior of said chamber.

References Cited in the file of this patent UNITED STATES PATENTS1,403,804 Merrell Ian. 17, 1922 1,466,579 Collver 'Aug. 28, 19232,066,281 Traylor etal Dec. 29, 1936 2,596,086 Muller May 6, 1952FOREIGN PATENTS 12,096 Great Britain June 13, 1901 330,805 Great BritainJune 19, 1930

